BIOL 160
Integrated Medical Science Lecture Series
Lecture 11, Skeletal System
By Joel R. Gober, Ph.D.
>> All right, so today is February 22nd. We got a quiz today, you’re all probably aware
of that, and then a take-home quiz of Skeletal System which will be pretty easy, but you
got to spend some time doing this. And, but don’t forget the test on Monday.
>> Tuesday.
>> Yeah, Tuesday.
>> It could be Monday.
>> Yeah, you got one more day. And here, the exam figures, I’ve re-arranged. I cut a
bunch of figures off the list. I saw figure 7.1, figure 7.11, figure 7.20, could be on the
test. I could photocopy those, put them on the test and have you label everything as
labeled on those diagrams. Furthermore, figures 7.8, A & B, 7.18, ABC, I might have
some questions relating to those figures. And then I’m going to talk about those figures
today, but you don’t have to memorize them, but it you do memorize them, then that will
help you answer the questions, so. But you’re not going to have to label them. Okay.
And that’s because we’re supposed to have two lectures on the Skeletal System but we
only have time for one, so I have to cut something back.
>> What about 7.16 B?
>> No. That’s not going to be on the test.
>> You said they’re just going to be on [INDISTINCT], that was on the textbook
[INDISTINCT].
>> But if you’re going to [INDISTINCT].
>> I’m sorry?
>> Within the period they’re going to be like blurry.
>> Maybe a little blurry.
>> So, we could ask [INDISTINCT].
>> Okay, we’ll [INDISTINCT]?
>> The [INDISTINCT]
>> That was on.
>> [INDISTINCT]
>> I don’t have a screwdriver.
>> All right.
>> It didn’t [INDISTINCT]
>> This [INDISTINCT]
>> Now I got to go over what might be on the test for you.
>> Does 7.3 [INDISTINCT]?
>> No. No. Okay. I think this is 7.1. Long bone, we’ve covered a long bone.
>> Uh-huh, okay.
>> Okay. Huh?
>> Yeah, uh-huh.
>> Yeah, ‘cause I can’t show you a picture, I’m just going to draw in the board
something.
>> [INDISTINCT]
>> Yeah. It’s going to be epiphysis, diaphysis, all that kind of stuff. Okay. So, when
you have a long bone, a long bone is, for instance, in your arm over here. There’s one
dimension that’s very long compared to the right-left dimension is very short, and to your
posterior dimension is very short as well. There’s only one dimension in a long bone
that’s long compared to any other way. So a typical long bone looks like this. It got two
ends, right? All right, the ends we call epiphysis. So, here’s an epiphysis and here’s an
epiphysis. And this one up over here, the one that attaches through some location of your
body, we call this the proximal. And the one down over here is what we call the distal,
because it’s farther away from some attachment point to your body. You see that figure
in your book, if you have your books?
>> Yeah.
>> At 7.1? Nice. Okay. All right. And then you got all this bone in between the
epiphysis. This is what we call the diaphysis. So, another name for diaphysis of a bone
would be the shaft of a long bone, the shaft of a long bone. So you got the epiphysis and
the diaphysis. Furthermore, on the inside of the bone, you don’t have solid bone, you
have little bony plates with a lot of spaces between them, and we call this spongy bone.
Okay, that’s spongy bone, because it looks like what? It looks like a sponge. All right.
Then on the surface of the bone, right here, this is solid bone, everywhere you look, that’s
solid bone. And solid bone, we call it compact. So, compact bone is certainly stronger
than spongy bone, but spongy bone is a lot lighter so it doesn’t require as much muscle to
move it around. If all of your bone was compact bone, we probably couldn’t even get up
because you’ll be way too heavy. Okay?
>> The term it used is the cancellous.
>> Cancellous.
>> And it’s another one?
>> Cancellous.
>> Okay.
>> Cancellous. I don’t think that’s in your book. Okay.
>> That was in the Study Guide.
>> That was in the Study Guide? Oh, okay. Yeah, I’m not going to ask that kind of
question. In the very center, right here of a long bone, there’s a cavity. And whenever
you have an organ, and a bone is an organ, you have a superficial part which is called the
cortex. So, compact bone sometimes is called cortical bone/compact bone ‘cause it’s
right on the surface, it’s superficial. And the deepest part of an organ is always called the
medulla. Cortex is a superficial, so that cavity is called the medullary cavity, because it’s
deep inside the bone. But that cavity is filled with stuff. It can be filled with one or two
kind of things. It’s always going to be called marrow, but the kinds of marrow, one
would be yellow and the other would be red. And if it’s yellow, that’s just a storage form
of fat or adipose tissue. If it’s red, all right, if it’s red bone marrow then that’s for blood
production. So, the medullary cavity is there to make bones lighter without sacrificing
strength but it can also be filled with something, either yellow bone marrow or red bone
marrow. And if it’s yellow bone marrow, it’s for storing fat, if it’s red, then it’s for
making red blood cells.
>> Could you have both?
>> Huh?
>> Could you have both?
>> Could you have both? Maybe not exactly in the same location, but it might slowly
transition from one to the other. Yeah. But in somebody, our age, most long bones are
completely yellow bone marrow, but in younger individuals, it’ll be completely red bone
marrow, and where it transfers over, I’m not really sure.
>> Uh-hmm.
>> Yeah, so somebody in intermediate age might have a little bit of everything going on
in there. Okay. All right, now, can you remember from—did I go over everything on
that diagram? Pretty much. Oh, except one last thing. In this region right here, there’s
something special going on. This is called epiphyseal plates. The epiphyseal plate is
where the bone is growing in the long direction. So, you have the distal epiphyseal plate
and there’s proximal epiphyseal plate, so bone grows in length in this direction right over
here, okay, in a long direction. And there’s a lot of cartilage in this epiphyseal plate
when it’s growing. And what’s the stronger kind of tissue, cartilage or bone?
>> Bone.
>> Bone is a lot stronger, right? So, that if somebody, if a youngster is really horsing
around, okay, and jarring their body, right, the muscles are going to push on the distal
epiphysis and push on this diaphysis and it’s going to squish, what?
>> The [INDISTINCT]
>> The epiphyseal plate. Okay. In which case, this epiphyseal plate is going to be
damaged, and if the epiphyseal plate is damaged, guess what happens to the bone growth
then?
>> [INDISTINCT]
>> Yeah, it’s going to be attenuated or maybe it’s going to be stopped or certainly it’s
retarded, somehow. All right. And what happens to the length of this bone, then? It
doesn’t grow to its normal natural size. So, if you have any youngsters like to swing
on—this swing, you know, like we all used to do and get to the highest point and then
jump off.]
>> Yeah.
>> All right, then fly through the air, flying is really cool. Unfortunately, landing is
really hard and in particular on what? These epiphyseal plates right here. And if they’re
damaged, then that limb is going to be stunted in growth, and it might be just one leg or
the other. It might not be bilateral, in which case, one limb will be a lot longer than the
other by the time you grow up. Okay. So, that’s an important consideration. Now, when
did these epiphyseal plates ossify? A bone will stop growing at a particular time. And
when it actually turns from cartilage to bone, that’s when a person stops growing in
height. Okay. And that happens right at puberty, we’re pretty close to puberty in most
cases. All right. So, after puberty, we’re not so concerned about these epiphyseal plates
because they turn to bone anyway, and you can’t really damage them more than any other
part of the bone. This is also interesting because you can see, then, at least within a
family, who is typically taller, are the men or the women, typically taller?
>> The men, sir.
>> Men are typically because who reaches maturity sooner, women or men?
>> Women.
>> Women do. Right. So, women will mature at an earlier age, these epiphyseal plates
will stop growing, while a man or a boy will still won’t reach maturity yet for a couple of
years, they’ll continue growing, okay, past that age. So, at least, within a family, men are
a little bit taller. Okay. That’s not generally true across the board, but at least within a
family that’s pretty true. But then again, if you’re a woman, you might have a brother
that’s shorter with you and that’s just, you know, some genetic variation. Okay. So,
that’s it for a long bone. We’ve gotten all the parts and those epiphyseal plates. Yeah.
>> [INDISTINCT].
>> Okay. A plate is that 3-dimensional structure that’s inside the bone, but if you cut the
bone you just see that one line. Okay. So, yeah, it’s pretty much the same thing. Okay?
But the epiphyseal plate is the growth plate, but even in an adult, that area, where there
was a growth plate, is ossified, has a lot of calcium and it makes that little line. So, I
would say maybe the plate is the growing center and the line is just where the plate was
before puberty happened. Okay. Let’s talk about some cells. I think you learned
subcells when we talk about tissue. Okay. So, in this area when the bone is growing,
when the bone is growing right here as oppose to—so let’s just say this is a mature bone
here. A mature bone, and when we look at connective tissue, we said any—what’s the
name of the cells that we found in mature bone? They’re called…?
>> Osteo…
>> Osteocytes. Because osteo means bone. So, those are just kinds of cells that are in
bone right here. But the cells that make bone are actually called, in these epiphyseal
plates, osteo-something because it’s bone, but osteoblast. These are osteoblasts. So,
osteoblasts are building bone, they’re laying bone down, and then after the bone is made,
they turn into osteocytes. But don’t forget, as the bone is growing, okay, specially, okay,
there are other cells, in fact, this medullary cavity right here, they break bone down, they
make the cavity. And the cells that make the cavity are called osteoclasts. Those are
osteoclasts. So you got three types of cells, the osteocytes in mature bone, the
osteoblasts, but you say, build bone, and the osteoclasts, that’s a good word, well, break
bone down, but I want a word that matches with the C right here and I can’t think of one.
It cannibalizes bone. It breaks it down. Osteoclasts, okay, breaks it down. Breaks bone
down. Okay. So, I know there’s a question on the test regarding this three cell types.
All right. That’s one of the study questions. Know the definition for osteocyte,
osteoblast and osteoclast. Number 6. Wow, without a projector this is really tough.
>> Let’s go home.
>> No, I can’t let you go home.
>> Can we borrow or something?
>> Please. Huh?
>> [INDISTINCT].
>> Yeah. Let me see first, see if there’s a class next door.
>> [INDISTINCT].
>> Oh, maybe I should just kick the socket, huh? Maybe this is the socket, now I—
probably not. No, the fan was on. Okay. I guess I don’t know how to use this machine.
Okay. I thought it was pretty simple. Okay. The skeleton could be thought of as
generally two different areas. So, let me erase this, ‘cause this is a question on the test,
too. Okay. You got the whole skeleton, and the first part is what we call the Axial
Skeleton. The second part is what we call Appendicular Skeleton. The axial skeleton
contains bones of the head. Okay, bones of the head, the vertebrae or vertebral column,
your ribs and then your sternum which is the breast bone right here. And your
appendicular skeleton has to do with your appendages namely your arms and your legs,
or your upper appendage and your lower appendage. Okay. Arms and legs. I’m really
close to giving this quiz.
>> [INDISTINCT].
>> [INDISTINCT].
>> Let see if there’s anything that I can go over that makes sense.
>> Yeah.
>> Okay, without showing you. You know, I think I’m just going to keep… It just
seems that the test is already run-off. I can’t change the test. But it’s okay if you don’t
answer the questions, but…
>> Explain the questions.
>> Yeah, that’s basically what I decided to do today, we’re just to go down through the
questions.
>> [INDISTINCT]?
>> Yeah. Okay. So, the questions on the test according to the Study Guide right here in
Chapter 7, number 3. All right, so number 1 and number 2 are not on the test, it’s just
number 3. What are the parts of a typical long bone? And we went over that, right? The
epiphysis and diaphysis and all that kind of stuff. Number 4 is not on the test. Number 5
is not on the test. That’s pretty easy, because number 5 is what kind of tissue is the bone,
well, it’s connective tissue. And what kind of ions are in there or what kind of minerals
are in there, well, you think calcium, right, so that’s not really difficult. Number 6, that is
on the test, know the definitions for osteocyte, osteoblast and osteoclast. Which one
builds bone?
>> Osteoblast.
>> That’s the blast. Which one cracks it up? Oh, that’s a good one.
>> Osteoclast.
>> Osteoclast. And then mature bone is…
>> Osteocyte.
>> Osteocyte. All right, bones of the axial skeleton. It’s the head and the vertebrae, the
ribs are axial skeleton. And I think there’s one question on that.
>> [INDISTINCT].
>> It needs to process axial skeleton [INDISTINCT].
>> [INDISTINCT].
>> I got number 7, what are the bones of the axial skeleton?
>> [INDISTINCT].
>> No, I’ve seen that. I went over this in the past and the first one is [INDISTINCT] it
was the same thing.
>> Yep. That should be the same thing.
>> [INDISTINCT] thoracic cage.
>> Thoracic cage would be vertebrae and ribs. Those part of it.
>> Yeah, what about the hyoid?
>> Hyoid bone, you know, that’s a funny bone and it’s a little horseshoe-shaped bone
that’s up in your jaw. So, it’s up in this area over here. And it’s really important for
swallowing and articulation, so it’s an important bone. If for instance, if you’re going
into speech pathology or something like that, but it’s not a bone that’s typically we’ve
seen, you can’t really palpate it, you can’t feel it, because there’s so much muscle around
it. And if you push hard enough to feel it, chances are you’re going to break it because
it’s kind of delicate. Okay. But it’s, it kind of follows the contour of your mandible here,
but it’s inside your jaw, that’s inside the jaw. Ribs, okay. Number 8, there’s a question
on the test regarding number 8. Your vertebral column. I’m just going to draw this out
like saw. Here are your—all the vertebrae, and there’s vertebrae number 1 and number 2.
This region right here is called cervical and that’s your neck. Your cervical vertebrae are
in your neck. And you have seven of them altogether. The next division we call
thoracic, and there are 12 of them. The next division is lumbar, and you’ve got five. And
it’s pretty easy to remember how many there are in your neck, how many there are in
your thorax and how many there are in your lumbar region.
>> So [INDISTINCT].
>> And then you also have sacral and coccygeal, okay, which I’m not going to really talk
about. Sacral they’re there, and then your tailbone are your coccygeal. But your tailbone
is not really important ‘cause we don’t wag it around anymore. Okay. Okay, cervical is
in your neck. The first one right here is called the atlas because that’s holding your head
up. And remember that mythological god named Atlas? What’s he doing? He’s holding
up the whole world. I don’t know from what mythology it is, probably a number of
different cultures. Atlas is holding up the head. All right? And the next one is called the
axis. This is number 2, right over here. And those are the only ones that have names.
All the rest just have numbers, like number 1, number 2, number 3, all the way down to
which one?
>> Seven.
>> Yeah, number 7. And then thoracic number 1, all the way down to?
>> Twelve.
>> Number 12. Okay. So, how can you remember cervical 7, thoracic 12, lumbar 5?
>> [INDISTINCT].
>> Yeah, because you get up have breakfast at 7, lunch at noon, dinner at 5. Is that really
stupid or what? But I know all kinds of good stupid things to help you remember things
like that. Okay? All right. I don’t think that question is on the test, but you might have
atlas or axis, number 1 or number 2, they’re cervical vertebrae, on the test for instance.
Okay. So, the axis is kind of an interesting vertebrae, and that’s in, I think, this figure
right here, shows the different kind of vertebrae. Most vertebrae have a body that looks
like this and then a spine sticking at the back. So, this is the body right here, and this is
the spinous process. And they’re flat, here and here. And so another vertebra is going to
fit, how, right on top of it, like that, and another one is going to fit right on top of it like
that. All right. Except for number C2. C2 has a special spot sticking up like this. And
this is what we call the Dens and it sticks up, right around C1. So, I’m going to put a
dotted line right here because what, it’s behind C1. So, think of C1 as being a tire around
this axle, the dens. So, we have two vertebrae, okay, on top of each other, with that axis
are the dens sticking up and this just allows these two vertebrae two rotate around each
other. So, the dens allows you to do this kind of motion. It’s no motion, it’s a rotation,
okay, because of the dens that’s sticking up. Those two vertebrae can just rotate right
around each other. Let’s talk about ribs for just a second. I think that is maybe this
diagram right here. Okay. By definition, where is the rib attached? It attaches to our
thoracic vertebrae. And if you have 12 thoracic vertebrae, how many pairs of ribs?
>> Twelve.
>> You’re going to have 12. So, a rib can only attach to a thoracic vertebrae. If you
have, and this happens, not too infrequently but it does happen, maybe you only have 11
ribs. How many thoracic vertebrae do you have?
>> [INDISTINCT]
>> You know what, then, by definition you have 11. Okay. So, there’s got to be a one to
one correspondence between the number of ribs that you have and the number of thoracic
vertebrae. So, if you’re missing the 12th rib, then you’re missing this 12th vertebrae here
as well. You don’t get an extra rib anywhere. The first five, one through five, are what
we called true ribs. And the remaining are what we called false ribs, because these two
ribs, if we look now at an anterior diagram of somebody, this is their breastbone right
here, and the breast bone we called the sternum. And does anybody know what this
whole piece? This inferior little piece sticking up in sternum is called?
>> Xiphoid.
>> That’s a xiphoid process. And when people undergo CPR, they got to be concerned
about that little xiphoid process because they can break off the sternum and can go into
your liver and lacerate the liver for instance. All right, I might have the xiphoid process
on the test. The xiphoid process is part of the sternum right here, while a true rib,
namely, this first five, attached directly to the sternum. Like this, these are true. So,
these are the true ribs, right here. False ribs are going to come around to the back or from
the back but they’re going to attach to rib number 5, not directly to the sternum. So, this
would be what, like number 6 and number 7, number 8, all right, 9, 10, are going to
attach via cartilage to rib number 5. So, these, since they don’t attach directly to the
sternum, we call these false ribs. Furthermore, you got two more, right, because we only
got to 9 okay, and 10. There are two additional ribs, number 11 and 12, they don’t attach
at all. They’re just floating. They don’t attach to any other ribs or to the sternum, so,
these are what we call floating ribs. Okay? Floating ribs are also false. So, not all false
ribs are floating, only the posterior, only the inferior 2 are floating. So, superior 5 are
true, the inferior 7 are false and furthermore, the most inferior 2 are called floating ribs
because they don’t attach to any ribs, whatsoever, they’re back over here. So, if
somebody gives you a big strong bear hug, these are the ones that you can actually break,
all right, because they’re not very strong, they’re not attached to anything. Okay. True
rib versus false rib, that’s number 9. So, a true rib is what, attached directly to the
sternum and a false rib is not directly attached to the sternum. And I think maybe there’s
a question about the sternum on the test and maybe that xiphoid process, which leads me
to think of when we name bumps on bones, there is something called a process. Okay, a
process. Let’s say bump on a bone, like when I drew this thing, this spiny process
sticking off the body of a vertebrae, I called it a process. The function of a process is
always muscle attachment. So, process is muscle attachment. There’s another thing on a
bone, for instance if we have a bone right here and there’s a hole in it. We don’t call it a
hole, we give it a special other name, we call it a foramen. And it’s got a different
function. So, if you ever read something foramen and somebody asks you what the
function of that particular foramen, you don’t have to know specifically what’s going on
there but just like if anybody asks you what’s the function of this particular process, you
immediately would say muscle attachment. All right? But if it’s a foramen, it’s a
passageway for something. And plural, all right, we would say, A. Foramina would be
plural for foramen.
>> This spell like foramen?
>> For-, yes, F-O-R, and then A. F-O-R-A-M-E-N, foramen, and then foramina for
plural. So, in general, I could ask you, what’s the function of a transverse foramen?
You’ve never heard of a transverse foramen, but you would just say it’s a passageway
‘cause it’s a hole in a bone. It’s a passageway for maybe a nerve going through the bone
or a blood vessel going through the bone, maybe even a muscle going through the bone.
Okay. But if we say what’s the function of a process, you wouldn’t say passageway, you
would say muscle attachment. Okay. Okay, number 11. Appendicular skeleton, you got
to look at that figure, I think it’s this one right here that shows the bones of the
appendicular versus the axial skeleton. So, look at that. The last thing on that diagram
is—so, here is—what’s that? That’s your skull, that’s your head, right? Here is your
vertebral column and your ribs, something like this, right, and your sternum with your
xiphoid process right there. All right, so, that’s all axial skeleton. Now, what about this
right here? And this right here? And this here? What skeleton is that?
>> [INDISTINCT].
>> That’s the appendicular skeleton, these are your appendages, right, your arms and
your legs, right here. So, your skeleton is made of axial versus appendicular. And then
you have a couple of bones that attach your appendicular skeleton to the axial skeleton.
For instance, in this region right here and this region right here. Those have got special
little names. And these are what we call girdles. So a girdle attaches appendicular
skeleton to axial skeleton. Appendicular to axial, that’s a girdle, and you got two. The
ones up over here in your shoulder are what we call the pectoral girdle. And the one
down over here, anybody know what that thing is called?
>> Pelvic girdle.
>> That’s the pelvic girdle. So, some on your test has got a question, it probably is going
to ask maybe what are the bones of the pectoral girdle or what are the bones of the pelvic
girdle. Okay. And I don’t know which question it is, but the pectoral girdle is made of
the scapula and the clavicle. And your clavicle you can feel pretty easy, that’s his bone
right up over here, and your scapula is in the back. So, take a look at a picture of where
the scapula and clavicle are. All right, the pelvic girdle are your hipbones, but we don’t
call them hipbones, they got a different name, they’re called your ossa coxae. So, your
pectoral girdle is your clavicle and scapula, and your pelvic girdle is your hipbones or
your ossa coxae. So the girdles really are part of the axial skeleton or the appendicular
skeleton, they attach the two together. That’s number 11. Number 14, know the
characteristics of a synovial joint. Okay, synovial joint—there are different kinds of
joints, some joints are immovable, like there are joints between the bones of your head,
and they don’t move. Of course, that’s not a synovial joint. But your shoulder is a good
example of a synovial joint because you have a huge range of motion. So, synovial joint
is really movable. So what’s the function of a process?
>> Muscle attachment.
>> Muscle attachment. What’s the function of foramina?
>> Passageway.
>> Passageway. Okay. All right, so what was I talking about? Oh, synovial joints. All
right, well, I didn’t say what a joint is yet. What the heck is a joint? A joint is an
articulation or connection between two bones, right? So, if you have one bone and
another bone where they come together, all right, that’s a joint, and some joints are
immovable, other joints are feely movable. Freely movable joints are what we call
synovial. So what’s a good example of a synovial joint, like the shoulder? Your hips are
synovial joints, and these are an interesting kind of synovial joint. For instance, in the
scapula, this is going to be scapula right here, I’ll go write it bigger. There is a big
depression, okay, and in that depression, the head of a long bone fits in. So this looks
like a socket, and this thing right here looks like what, a ball. So, this kind of joint, a
shoulder and a hip, is called the ball and socket joint and it just allows for a lot of degrees
of motion, right? So you can do almost anything with your shoulder and your hips
because it’s a ball and socket joint as opposed to a finger. That’s not a ball and socket,
that’s just a hinge that can only go backwards and forwards. Okay, back and forth. And
if you bend it in any other which way, what does that mean?
>> Oh.
>> Something’s going to break, okay? But the nice thing about a ball socket, you can
move it any which way and nothing’s going to break. Okay. So finger joint is still
synovial because it’s what, freely movable. But it’s not a ball and socket. Your knee is
another example. What kind of joint is your knee?
>> Okay, it’s synovial, it’s freely movable, but again, it’s not ball and socket, it’s what?
It’s just a hinge joint. Okay, that’s a hinge. That joint between C1 and C2 over here,
Cervical 1 or Cervical 2, atlas and axis, that’s not a hinge joint. All right, that’s what we
call a pivot joint because it just allows for rotation. So, there are different kinds of joints,
but again, that would be a synovial joint because it’s what, it’s freely movable. Okay. So
for number 15, I want you to know that a ball and socket is a synovial joint, right, like
shoulder and your hip. There’s another kind of joint that none of us have, but newborns
have neonates have. There are special joints between the bones of their head, right,
because the bones of their head are not completely formed. And it’s a good thing that a
neonate’s head can actually deform quite a bit that it’s getting squished out the birth canal
‘cause it’s good for the baby and good for the mom, right. So, the head can deform a
little bit, it can compress, come out the birth canal, and those joints are formed by
membranes. And what do we call those membranous spots in a neonate’s head that are
very soft?
>> Soft spot.
>> Yeah, they’re the soft spots, that’s definitely what we call them. Common, but there’s
a scientific name formed, too.
>> Fontanelle.
>> So soft spot, certainly is one, all right, but that’s the exact same thing as a fontanelle,
a fontanelle. And does anybody know about how long fontanelles can stick around in a
neonate?
>> Two to three [INDISTINCT]
>> Yeah, it could be as long as two years, so that’s way past being a newborn. So, you
got to be really careful with these little kids because they have those soft spot, they don’t
have a hard cranium to protect their brain for, maybe, as long as two years. So any kind
of shaking, right, can be very damaging to their nervous system or any kind of puncturing
is certainly very damaging. All right, and in your book, you have a nice picture of a
fontanelle, a number of fontanelles in a neonate’s head. There’s a little dog that has
fontanelles their whole life, does anybody know? Huh?
>> Chihuahua.
>> Yeah, Chihuahuas have fontanelles their whole life, they’re kind of interesting, so...
>> [INDISTINCT] Chihuahuas?
>> Huh?
>> You never play with Chihuahua?
>> Well, I probably wouldn’t want to have a Chihuahua and have them play with a
Rottweiler or a Doberman or something, okay, because just a little slip of that canine
from the Doberman could go right through the head of that Chihuahua because it doesn’t
have a hard cranium in that spot. Yeah, so—and of course, any kind of trauma, shaking
or whatever, they would be susceptible, yeah. Okay.
>> [INDISTINCT] that means to know or [INDISTINCT]...
>> Ball and socket. Ball and socket, freely movable joint. Yeah. So if you see a
question about which kind of joint is freely movable, you know what, a ball and socket is
freely movable.
>> As well as shoulders and the hips.
>> Huh?
>> Shoulders and hips.
>> Your shoulder and hip. Your shoulder and hip are the only two examples of ball and
socket joints that you have.
>> Aren’t they all synovial?
>> Are all joints synovial?
>> No, like of all the ones right here listed in number 15.
>> Number 15. So, all the ones that I’ve listed, yeah, plane and gliding, a pivot, a hinge,
ellipsoid, saddle are synovial joints. Oh, there’s no way I can show you how those work
except hinges are easy, okay? Example of a saddle joint would be your thumb. All right,
your thumb it can move like this but it can also move like that. So your thumb joint is a
little bit more complex, it’s not just a hinge, but it’s not quite as movable as what, a ball
and socket, but it’s getting there. Okay. The last thing that I want to talk about is
motion, that produce different kinds of motions in your body. Okay. And that’s number
17. So, 16, well, 16 is—are things that work against each other. Okay, antagonism. And
we talked about three cells, three kinds of bone cells. What were those three kinds of
bone cells again?
>> Osteo something.
>> Osteo something. Osteoblasts build bone.
>> Osteoclast.
>> And what kind that break bone down?
>> Osteoclast.
>> [INDISTINCT].
>> Clasts. The clast break it down, the blast build it up. So, these two are working what,
against each other, because they do opposite things. Those cells are what we call
antagonistic to each other. Okay. So, the clast and the blast are antagonistic. All right.
Osteoblast is antagonistic to what, the osteoclast. If that breaks bone down, that builds
bone up. And those two cells are always working in our bodies all the time. So, once
your body builds a bone, it’s not there forever. As a matter of fact, all the bones in your
body are completely replaced every five years. So that just shows you what? That the
osteoblasts are very busy and the osteoclasts are very busy, and if you have healthy bones
then there’s a balance between the two. And who could—what’s the name of that
process where there’s an imbalance in these two cells? Maybe the osteoclasts get too
busy and the osteoblasts can’t keep up with them. What’s that called?
>> Osteoporosis.
>> That’s called osteoporosis. All right, so there’s some kind of imbalance that happens
to everybody, if we’re lucky enough to live long enough but particularly women, okay.
That imbalance seems to show up a little bit more and especially women who have very
thin bones as opposed to women who have thicker bones. And one way to protect
yourself, if you’re a woman, from osteoporosis is that any kind of exercise that you do
has a tendency to build bone up. So, good diet, pre-menopausally where you have good
calcium in your diet, good vitamin D and exercise will protect you from osteoporosis
later on in life. Okay. But if you’re fortunate enough to be a woman with big, strong
bones, then you don’t have to worry quite so much about osteoporosis. Okay. But even
men get osteoporosis, and in every woman, well, to some degree. Okay. So, that’s
antagonism. Along the lines of antagonism, certain kinds of motion. Flexion and
extension. Let’s talk about flexion and extension, these kinds of motion. All right, if we
think of your arm, all right, especially at the elbow right here, you have bones in the
forearm and bones in the arm. If we decrease the angle between your forearm and arm,
that’s what we call flexion. So decreasing the angle is flexion. If we increase the angle
between these bones, that’s what we call extension. So, flexion and extension are
opposite terms, and you know what, they’re antagonistic to each other as well. All right.
So, flexion opposes extension, and extension opposes flexion. I think maybe there’s a
question on the test regarding flexion and extension. Okay, so this would be a good
example. So what’s this motion right here that I’m doing now? Boom.
>> Flexion.
>> It’s flexion. And when I increase that angle that is?
>> Extension.
>> Extension. If you have your hand like this, what is this motion?
>> Flexion.
>> That’s flexion. Yeah, flexion. And this would be…
>> Extension.
>> Extension, so flexion and extension. You can flex your vertebral column. I can’t
really do that anymore. But if you contract your stomach muscles and you bend your
vertebral column like this, okay, that is flexion of your vertebral column. But if you
stand up straight like that, that is extension, all right, so flexion or extension of your
vertebral column. What about your leg? What is this motion right here going like this?
>> Flexion.
>> That’s flexion and this is extension. All right, so that’s not too hard to know. Maybe,
one more, adduction and abduction. If you have your limbs and you move limbs away
from your body, this is abduction with the B, abduction. All right, but if you bring your
limbs towards your body, you can do that with your legs, too. Okay, bring your feet
together, that’s adduction. So, abduction, adduction. So, adduction is when you add
your—add things together, when you bring things together, it’s adduction. When you
bring things apart, that’s abduction. You can abduct and adduct your fingers as well, and
I think maybe you saw that when I was working with the fingers, right? When you
spread your fingers apart, what’s that called?
>> Abduction.
>> Abduction. And when you bring your fingers together, that is?
>> Adduction.
>> Adduction. And you can do that with your toes too, right, you can abduct and adduct
your toes back and forth. All right, so you can abduct, adduct, and what’s this again? It’s
flexion, extension.
>> Yeah.
>> Okay, flexion and extension. And those are what we called antagonistic motions.
Okay. Those others, maybe I might go over some time ‘cause they’re interesting, ‘cause
a lot of people hurt joints by making their body do things that those joints aren’t supposed
to do. We talked about rotation. We can—the bone in your upper arm is called the
humerus. All right, we said flexion and extension, but if you bring, if you flex your
forearm and bring your forearm over like this, we can get the humerus to rotate. All
right, so I’m not flexing or extending, I’m just rotating the humerus right here. So this
would be a lateral rotation, a medial rotation. A lot of people have trouble with their
shoulder called rotator cuff injury, that’s a problem with rotation at the shoulder. Now, a
good clinical sign, a good test for a rotator cuff injury is when they try to do a lateral
rotation, if there’s resist-, when you put resistance to a lateral rotation, that produces
excruciating pain in the shoulder. That would be a nice sign of a rotator cuff there. All
right, so knowing motions of joints is you just run into it all the time. Okay. Well, I got
a quiz for you.
>> [INDISTINCT]
>> Right.
>> Which figures you got to know? You got to know 7.1, 7.11, and 7.20.
>> Well, that’s the one in the bottom though? [INDISTINCT]?
>> One is 11 is, but 20 is not. I want you to add 20, but I want you to delete 16 and 3,
right? Yeah, delete 7.16, delete 7.13. But now, if you look at those, they will help you in
the test but it’s not absolutely crucial.
>> Well, do we need to know 4.7, 5.1, and 5.2?
>> Yeah, you still need 4.7, 5.1, 5.2, 5.3, 5.5 and 6.1.
>> All right.
>> Okay.